Fuel feeding mechanism for mechanical stokers



Dec. 26, 1933. e. AUER, JR 1,941,197

FUEL FEEDING MECHANISM FOR MECHANICAL STOKERS Filed Feb. 5, 1929 2 Sheets-Sheet 1 Y I 4M,M

A RNEY Dec. 26, 1933. G. AUER, JR 1,941,197

FUEL FEEDING MECHANISM FOR MECHANICAL STOKERS Filed Feb. 5, 1929 2 Sheets-Sheet 2 INVENTOR m BY ATTORNEY Patented Dec. 26, 1933 UNITED STATES FEEDING MECHANISM FOR MECHANICAL 's'ro Ens Gustavus Auer, Jr., Philadelphia; la. Y Y Application February 5, 1929. Serial-No. 337,581 Claims. (01410 -24) Furnaces for the burning of solid fuels varying widely in moisture contentfrom coals to waste fuels such as sludges, separator cleanings and similar materials, have heretofore been constructed with refractory lined combustion chambers,

feed hoppers, ignition arches, bridge walls and grates, and the fuel is fed from the feed hopper to coking shelves by means of reciprocatory fuel pushers. J r

The green fuel-is subjected on the coking shelf to the intense heat of the furnace, causing it to ignite and the volatile matter is driven off with the gases of combustion. The solid portion of the fuel remains on the coking shelf in theform i of a' coke residue which-adheres to the shelf and gradually builds up in front of the pushers and closes thefeed opening; It is then necessary to stop the pushers and clear the shelf by means of hand operated bars. A plant is subjected to appreciable loss when it is shut down for such cause. 1

It is desirable in burning fuels containing large quantities of moisture or liquid to employ unusually long coking shelves which retain the fuel on the coking surfaces for longer periods of time in order todrive off the excessive quantities of moisture before permitting the residue to fall onto the grates. It is practically impossible to continuously move theburning fuel over such long shelves and prevent it from accumulating on them with thefuel p'ushers heretoforev employed.

To overcome this defect and make'it possible to continuously run the plant, I have devised novel means working in conjunction with the fuel pushers to prevent the accumulation of the fuel on'the coking shelves and overloading the fuel pushers.

To this end, I employ reciprocatory'slice bars and as these are subjected to the intense heat 1 of the furnace such slice bars and their connections are preferably made of heat resisting ma-i terial-and also in some cases of heat andacid resisting materials.

V The chambers of the slice bars are adapted to receive a temperature changing medium which may be of either. a heating or a cooling nature but which inmany cases is of acooling' nature.

With the above other objects in view as, will hereinafter more clearly appear, my invention comprehends a novel construction of a fuel feed-J ing mechanism of the" type herein disclosed: wherein the coking shelves are provided with slice or cutting bars which are mechanically moved along the shelves to prevent the burning fuel. accumulating thereon. 7

It further comprehends a novel furnacefof the type herein disclosed provided with a coking shelf, a fuel pusher, and a slice bar which is mechanically reciprocated in timed relation with the fuel pushers. The slice .bars are preferably arranged so that 3 they travel substantially the full length ofthe coking shelvesl' Other novel features of construction and advantage willhereinafter more clearly appear in the detailed description and the appended claims. For thepurpose of illustratingthe invention, I'have shown in the accompanying drawings, a

' typical embodiment of'it, which, in practice, will give satisfactory and reliable results. It ishowever, to-be understood that the various instrumentalities of which my invention consists can be variously arranged and organized, and'my invention'is not limited to the exact arrangement and organization of these instrumentalities, as herein set forth.

Figure 1 is a sectional elevation of a furnace embodying my invention. I v

Figure 2 is a'sectional view on an enlarged scale showing more clearly the fuelifeeding and ignition area of the furnace and the means employed for feeding the fuel. I 1 v Figure isa detail view sho wing more clearly the ccnstructionand arrangement of a fuel pusher and slice bar. a 1

Similar munerals of' r'fer'ence indicate corre-- sponding parts. 1 I --Referring to the drawingsz- The furnace is provided with the combustion" chamber 1 having a fuellhopper '2 through which the green fuel'is admitted to the-furnace. designates an adjustablefgate for regulating the amount of fuel which is being fed. I 4 'desig nates the reciprocating slice or cutting bars which operate -in advanceof-and either'in-synchronous or independent motion relatively to the "fuel pushers 5fby means of the connecting rods 6 which are attached to the slice bars within the furnace and eiitend through suitably shaped slots 7' iirthe bottom portion'of the fuel puehers 5 to a'point exterior of the furnace where the'y'are attached to connecting links 8 and the crank 9 from which they are driven through power shaft 10 on which the crank arms'9' are fixed f v T The 'shaft leis; actuatedfrom either end by means of any conventional type of prime mover.

The fuel pushers are similarly operated through connecting rods-24, crank arms 25 and shaft '26,

which latter maybe driven by means ofmotive power separate from that driving the slice ,bars

4 through the shaft 10.

The slice or cutting bars 4 may be made" of any desired material suitable for resisting heat, corrosion and erosion or the action'o'f acids. These bars extend laterally across the'width of the-furnace and operate on the upper faces of the'coking shelves 11. The connecting rods 6 and the slice bars 4 are suitably channelled by meansof internal passages 27 for the purpose of circulating the temperature changing fluids which are admitted and extracted through the flexible connecting tubing 28. These are in turn connected to any external system of piping for the transmission of the fluids.

12 designates ignition arches which serve to store and radiate the heat and reflect it down-' wardly on to the inwardly moving fuel on the shelves causing it to ignite so that the volatile matter and moisture in the fuel will be burnt leaving the coked residue to be advanced tothe grates 13. These ignitionarches 12 are located directly above a coking shelf.

14 designates a supply of a temperature changing medium such as for example cool or preheated air which passes to the air inlet jets 15 to be introduced thereby into the furnace above the coking shelves to assist in the combustion of the gases and a reduction of the smoke. The hopper is preferably provided with a fuel scraper 16 which is rigidly connected to the hopper and bears against the upper face of the pusher 5.

The lower shelf 11 is provided with a coke pusher 1'7 and a stationary scraper 18 bears against the upper face of such coke pusher. This shelf and coke pusher is merely shown for the purpose of illustration and may be omitted entirely in the preferred arrangement of the stoker. In this case the fuel would fall from a single coking shelf directly onto the grates 13.

The furnace is provided with a dead plate 19 extending laterally across the width of the furnace forming with the grate va dividing line between the combustion chamber 1 and the ash pit '20 beneath the grate.

21 is an air inlet duct providing for the introduction of the necessary air below the grate for the completion of. combustion of the fuel on the grates. The grates 13 are of any desired or conventional construction and as illustrated, they arethe conventional rocking bar type and may be either manually operated or power operated, it being understood, however, that in conjunction with my invention any desired type of grate mechanism may be employed.

The cokepushers 1'7 are connected by connectingrods 22 with the crank arms 9 and the front wall 23 of the-furnace is suitably apertured to permit the rods 22 to pass therethrough.

The slice andcutting bars 4 are low and flat in cross section as compared with the fuel pushers, and, as illustrated, they have flat bevelled surfaces on the top and plain flat surfaces on the bottom. The upper-marginal surface may be bevelled to different angles depending on the nature of the fuel to be handled and the nature of the results it is desired to attain. In some cases flat surfaces with the bevel omitted are preferred. It will be apparent that by altering the shape of these surfaces a wide range in performance may be provided. For example, by bevelingboth the inner and outer marginal edges, the bars may be made to pass under the mass of fuel on'the shelves merely breaking the adhesion 1 of the fuel to the shelves without-appreciably advancing the fuel. This permits the movement of the fuel to be accomplished by the fuel pushers without overloading them.

It will-thus be apparent that these slice and cutting barsmay act not only to scrape and break the adhesion of the fuel thereto but they may also act as auxiliary fuel pushers.

It will now be apparent that I have devised a new and useful fuel feeding mechanism for mechanical stokers which embodies the features of advantage enumerated as desirable in the statement of the invention and the above description, and while I have, in the present instance, shown and described a preferred embodiment thereof which will give in practice satisfactory and reliable results, it is to be understood that this embodiment is susceptible of modification in various particulars without departing from the spirit or scope of the invention or sacrificing any of its advantages.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. In a furnace provided with a combustion chamber, grates, a coking shelf extending into the furnace and superimposed above the grates, an ignition arch and fuel feeding hopper above the coking shelf which is adapted to receive the fresh fuel on its upper surface, the combination of reciprocating slice -bars operating on substan-.

tially the entire upper surface of the coking shelf to eliminate adhesion of the fuel to said shelf and progressively advance the fuel over the shelf, discharging the same onto the grates.

2. In a furnace provided with a feed hopper, a combustion chamber, grates, coking shelf and ignition arch, the coking shelf extending back into the combustion chamber above the grates and the normal elevation of the fuel bed, the ignition arch situated above thecoking shelf, the feed hopper adapted to discharge the fuel onto the upper surface of the coking shelf, the combination of slice bars operating on substantially the entire upper surface of the said shelf preventing adhesion of the fuel to the shelf and disintegrating the coking fuel and means to operate said slice bars.

3. In a furnace, grates, a coking plate, a fuel feeding hopper elevated above said coking plate, said coking plate extending into a combustion chamber above the grates and the normal elevation of the fuel bed, a heat radiating ignition arch above the coking plate directing heat onto the incoming fuel, mechanically operated reciprocating fuel pushers normally functioning to feed the fuel and auxiliary mechanically reciprocating slice bars mounted in advance of said fuel pushers and both pushers and slice bars operating on the same upper surface of said coking plate.

4. In a furnace, grates, a fuel coking shelf, a fuel feeding hopper elevated above a fuel coking shelf, said coking shelf extending into a combustion chamber above the grates and the normal elevation of the fuel bed and a heat radiating ignition arch above said shelf directing heat onto the incoming fuel, a main fuel pusher normally functioning to feed the fuel, an auxiliary'coke breaker operated on the upper surface of said coking shelf, and means for driving said pusher and coke breaker. V

5. In a furnace, grates, a fuel coking shelf, a fuel feeding hopper elevated above a fuel coking shelf, said coking shelf extending into a combustion chamber above the grates and the normal elevation of the fuel bed and a heat GUSTAVUS AUER', JR. 

